Campusleben_HAW_Hamburg_47

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Studierende_HAW_Hamburg_24

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Publikationen von Professorinnen und Professoren der HAW Hamburg

Jahr:  
Alle : 1982, ... , 2016, 2017, 2018, ... , 2020
Autor:  
Alle : A, À, B, C, D, E, F, G, H, I, J, K, L, M, N, O, Ö, P, Q, R, S, T, U, V, W, Y, Z 
Alle : Baars, ... , Blundell, Blättner, Blöß, ... , Böttcher 
Präferenzen: 
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Zeitschriftenbeiträge:

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Bernd Baumann, Jörg Schwieger, Ulrich Stein, Sarah Hallerberg und Marcus Wolff
High-intensity discharge lamp and Duffing oscillator--Similarities and differences
Journal of Applied Physics, 122(21):16
6 Dezember 2017
E

Marker: TI-MP

Zusammenfassung: The processes inside the arc tube of high-intensity discharge lamps are investigated by finite element simulations. The behavior of the gas mixture inside the arc tube is governed by differential equations describing mass, energy and charge conservation as well as the Helmholtz equation for the acoustic pressure and the Reynolds equations for the flow driven by buoyancy and Reynolds stresses. The model is highly nonlinear and requires a recursion procedure to account for the impact of acoustic streaming on the temperature and other fields. The investigations reveal the presence of a hysteresis and the corresponding jump phenomenon, quite similar to a Duffing oscillator. The similarities and, in particular, the differences of the nonlinear behavior of the high-intensity discharge lamp to that of a Duffing oscillator are discussed. For large amplitudes the high-intensity discharge lamp exhibits a stiffening effect in contrast to the Duffing oscillator. It is speculated on how the stiffening might affect hysteresis suppression.

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Bernd Baumann, Jörg Schwieger, Ulrich Stein, Sarah Hallerberg und Marcus Wolff
High-Intensity Discharge Lamp and Duffing Oscillator - Similarities and Differences
arXiv,
8 Mai 2017

Marker: TI-MP

Zusammenfassung: The processes inside the arc tube of high-intensity discharge lamps are inves- tigated by finite element simulations. The behavior of the gas mixture inside the arc tube is governed by differential equations describing mass, energy and charge conservation as well as the Helmholtz equation for the acoustic pressure and the Navier-Stokes equation for the flow driven by the buoyancy and the acous- tic streaming force. The model is highly nonlinear and requires a recursion proce- dure to account for the impact of acoustic streaming on the temperature and other fields. The investigations reveal the presence of a hysteresis and the correspond- ing jump phenomenon, quite similar to a Duffing oscillator. The similarities and, in particular, the differences of the nonlinear behavior of the high-intensity dis- charge lamp to that of a Duffing oscillator are discussed. For large amplitudes the high-intensity discharge lamp exhibits a stiffening effect in contrast to the Duffing oscillator.

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Johanna Buchcik, Joachim Westenhöfer, Mick Fleming und Colin R. Martin
Is Health-Related Quality of Life the same for elderly Polish migrants, Turkish migrants and German natives? Testing the reliability and construct validity of the Sf-36 Health Survey in a cross-cultural comparison.
Cogent Psychology, 4:1280984
16 Januar 2017

Schlüsselwörter: Elderly Turkish and Polish migrants; Sf-36 health survey; structural equation modelling; confirmatory factor analysis; reliability; Cronbach’s ?

Marker: LS-GW

Zusammenfassung: Objective: The Sf-36 is the most widely used instrument to measure health-related quality of life (HRQoL) with the most convincing evidence of both internal consistency and test–retest reliability. In addition, it is appropriate for use among elderly and minority groups like migrants. The aim of this study is to investigate and compare the reliability and the factorial structure of the Sf-36 in a sample of elderly migrants and natives. The hypothesis is that the construct (the HRQoL consisting of eight dimensions correlated with two components) is the same for elderly Turkish migrants, Polish migrants and German natives. This means that the Sf- 36 model shows good psychometric properties and model invariance for the three groups investigated in this study. Methods: The Sf-36 v.2 was forward and backward translated to Turkish and Polish. In this cross-sectional study, interviews were conducted with a sample of elderly migrants from Turkey (n = 100), from Poland (n = 103) and a sample of elderly German natives (n = 101). All data were entered and analysed using SPSS version 21 and AMOS Graphics. Cronbach’s ? was used to analyse the reliability of the Sf-36. Multi-group confirmatory factor analysis (MGCFA)and structural equation modelling (SEM) were used for the Sf-36 model invariance testing. Results: The reliability of the Sf-36 was good to excellent for all Sf-36 dimensions (? > 0.7) except for General Health (0.55) in the Polish group. Multi-group confirmatory factor analysis (MGCFA) showed non-invariance between the three groups (CMIN: 180.172, df: 51, CMIN/df: 3.533, p < 0.001, CFI: 0.895, RMSEA: 0.092 for the unconstrained model). Model modifications resulted in a good model fit for the Polish group. However, an applicable common Sf-36 model for the three groups was not attained. Conclusion: This study doesn’t support the idea that the factorial structure of the Sf-36 with two components and eight dimensions is the same across three ethnically and culturally diverse groups of elderly subjects. Therefore, comparing subscale scores of the Sf-36 between different ethnic groups may be problematic.

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Ulfia A. Lenfers, Rainer Brüggemann und Thomas Clemen
Exploring survival strategies of African Savanna trees by partial ordering techniques
Ecological Informatics, 42:14--23
2017
ISSN: 15749541

Marker: TI-I

Zusammenfassung: The resilience of savanna ecosystems to climate and land-use changes is an important ecological and management question. The term ‘resilience' is used to refer to the ability of a tree species to survive in a specific location, even under changing environmental conditions. In this study, vectors of functional traits of selected savanna tree species are studied by applying partial order algorithms to them. Some ecological interpretations are obtained and are compared to published research. One finding is the high rates of nitrogen fixation for the leaves of Acacia nigrescens. In opposition to this well-known fact, we discovered that Sclerocarya birrea has a bigger average leaf area than the other four tree species. Additionally, we found high carbonate values within the leaf from Colophospermum mopane, Combretum apiculatum, and Terminalis sericea. These results correspond to different ecological strategies for the tree species in question. It became obvious that geometric structures gained from partial ordering show a very good correspondence to ecological strategies of these tree species. Concepts of partial order theory may therefore be helpful in ecosystem research.

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C. Behnert und Dirk Lewandowski
A Framework for Designing Retrieval Effectiveness Studies of Library Information Systems Using Human Relevance Assessments
Journal of Documentation 73 (2017) 3, :509-527
2017

Marker: DMI-I

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Guy Beaucamp
Aktuelle Entwicklungen im Polizeirecht
JA, :728-733
2017

Marker: WS-PuMa

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Ernst Sanders, Björn Beckmann, Dorothea Hohmann, Moritz Eickmeyer, Sarah Bolz, Corinna Brodhagen und Petra Derr
An improved high cell density cultivation - iHCDC - strategy for leucine auxotrophic Escherichia coli
K12 ER2507. Eng. Life Sci. 17, :857–864
2017

Marker: LS-Bt

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Anne Wüstner, Luise Richter, Nele Mindermann, Nadja Kartschmit, Anna Barabasch und Christine Färber
Arbeit mit geflüchteten Frauen: Herausforderungen und Bedürfnisse von Hebammen - eine Interviewstudie von Studierenden des Masterstudiengangs Health Sciences
Deutsche Hebammenzeitschrift,
2017

Marker: LS-G

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Walter Leal Filho, L. Avila, L Brandli, C. Mac Gregor, P. Moltan-Hill, P. G. Ozuyar und R. M. Moreira
Barriers to innovation and sustainability at universities around the world
Journal of Cleaner Production, 164, :1268-1278
2017

Marker: LS

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Guy Beaucamp
Das Stichwort Gerechtigkeit in der amtlich gesammelten Rechtsprechung des Bundesverfassungsgerichts seit dem Jahr 2000
DVBI, :348-354
2017

Marker: WS-PuMa

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Letzte Änderung: 23.01.15

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